3-ethylene mercaptole derivatives of 6-methyl progesterone



United States Patent 3,162,629 .i-ETHYLENE MERCAPTGLE DERIVATIVES (FF e-nnrnrr. PROGEfiTERGNE Irving Scheer, Somerville, NJ., assignorto Births Pharmaceutical Corporation, a corporation of New Jersey No Drawing. Filed June 6, 1962, Ser. No. 260,347 12 Claims. (till. 260-4395) The present invention relates to a new group of thioketals of 6ot-methyl-progesterone-l7a-ol, and to esters of these thioketals.

The compounds of this invention are valuable pharmaceutical agents. The esters of 6ot-methyl-progesterone- 1711-01-3-ihi0k6l2fl1 possess anti-ovulatory properties and are effective in regulating ovulation. The acetate for example has practically no estrogenic properties and does not stimulate the endometrium yet prevents ovulation at lower levels than l7a-ethynylestra-4-en-17B-ol-3-one or 17a-ethynyl-5( lO)-estren-17B ol 3 one. Moreover the compounds of the present invention administered orally prevent ovulation at dosage levels well below those at which androgenic effects become prominent. The esters of the present invention can be administered in conventional dosage forms such as pills, tablets, capsules, syrups or elixirs for oral use. The products of the present invention may also be compounded in a form suitable for injection.

It is an object of the present invention to make available an oral contraceptive that will have minimal side eliects.

The starting materials for the compounds of the present invention are a-methyl-17ot-hydroxyprogesterone and its esters which may be converted directly to the desired S-thioketal.

CH CH ad n EXAMPLE I 6 u-M ethyl-4 -Pregnen-1 7ot-Ol-200ne-3-Thi0ketal A mixture of one gram 6a-methyl-4-pregnen-l7a-ol- 3,20-dione, 1 ml. of ethane dithiol, 2 ml. of methylene chloride and 1 gram of pyridine hydrochloride is stirred gently at room temperature for three minutes. The reaction is quenched by adding 30 ml. of methanol and cooling the flask in an ice bath for 2 minutes. The resulting precipitate is filtered, washed with ice-cold methanol and dried under vacuum at room temperature. The 6a-methylv 4-pregnen-l7e-ol-20-one-3-thioketal so obtained may be recrystallized from methanol-methylene dichloride to give 0.9 gram of a product melting at l86-188 C. The optical rotation in chloroform 0: is +99.

EXAMPLE II out-Methyl Pr0gester0ne-17a.-Ol Acetate To a stirred suspension of 6.0 grams of 6a-methyl-17a- 3,362,629 Patented Dec. 22, 1964 hydroxy-progesterone in 50 grams of glacial acetic acid is added 12 ml. of triflnoroacetic anhydride. A mildly exothermic reaction occurs and the solid gradually dissoives. The solution is heated on the steam bath for fifteen rninntes and then it is poured with stirring into 600 grams of ice-and-water. To this is added 250 ml. of methylene chloride and the mixture is stirred while saturated aqueous potassium bicarbonate is added until a strongly alkaline pH is attained. The methylene chloride layer is separated and is washed three times with cold 200 ml. portions of 10% potassium bicarbonate. After drying with magnesium sulfate, the methylene chloride solution is concentrated under vacuum.

The oily residue of the crude 17a-ester is chromatographed on neutral alumina to isolate the pure 6ot-methyl progesterone-lh-ol acetate, free of 17a-hydroxy compound, as shown by infrared spectrum. The yield of the desired ester is 78% of theory.

EXAMPLE III 6a-Methyl Progesterone-17a-0l-Pr0pi0nate To a stirred suspension of 6.0 grams of 6a-methyl-17ahydroxy-progesterone in 50 grams of propionic acid is added 12 ml. of triflnoroacetic anhydride. A mildly exothermic reaction occurs and the solid gradually dissolves. The solution is heated on the steam bath for fifteen minutes and then it is poured with stirring into 600 grams of ice-and-water. To this is added 250 ml. of methylene chloride and the mixture is stirred while saturated aqueous potassium bicarbonate is added until a strongly alkaline pH is attained. The methylene chloride layer is separated and is washed three times with cold 200 ml. portions of 10% potassium bicarbonate. After drying with magnesium sulfate, the methylene chloride solution is concentrated under vacuum.

The oily residue of the crude 17a-ester is chromatographed on neutral alumina to isolate the pure 6ot-methyl progesterone-l7a-ol propionate, free of l7ot-hydroxy compound, as shown by infrared spectrum. The yield of the desired ester is 65% of theory.

EXAMPLE IV 6a-Methyl Progesterone-170501 n-Valerate To a stirred suspension of 6.0 grams of 6a-methyl-17othydroxy-progesterone in 50 grams of n-valeric acid is added 12 ml. of trifluoroacetic anhydri-de. A mildly exothermic reaction occurs and the solid gradually dissolves. The solution is heated on the steam bath for fifteen minutes and then it is poured with stirring into 600 grams of ice-and-Water. To this is added 250 ml. of methylene chloride and the mixture is stirred while saturated aqueous potassium bicarbonate is added until a strongly alkaline pH is attained. The methylene chloride layer is separated and is washed three times with cold 200 ml. portions of 10% potassium bicarbonate. After drying with magnesium sulfate, the methylene chloride solution is concentrated under vacuum.

The oily residue of the crude l7a-ester is chromatographed on neutral alumina to isolate the pure 6a-rnethyl progesterone-lh-ol n-valerate, free of l7a-hydroxy compound, as shown by infrared spectrum. The yield of the desired ester is 71% of theory.

EXAMPLE V dot-Methyl Progesterone-1 7ct-Ol Cyclopentylpropionate To a stirred suspension of 6.0 grams of 6a-methyl-l7ahydroxy-progesterone in 50 grams of cyclopentylpropionic acid is added 12 ml. of trifiuoroacetic anhydride. A mildly exothermic reaction occurs and the solid gradually dissolves. The solution is heated on the steam bath for fifteen minutes and then it is poured with stirring into- 600 grams of ice-and-water. To this is added 250 ml. of methylene chloride and the mixture is stirred while saturated aqueous potassium bicarbonate is added until a strongly alkaline pH is attained. The methylene chloride layer is separated and is washed three times with cold 200 ml. portions of 10% potassium bicarbonate. After drying with magnesium sulfate, the methylene chloride solution is concentrated under vacuum.

The oily residue of the crude 17a-ester is chromatographed on neutral alumina to isolate the pure 60t-II1Cthyl progesterone 17a-o1 cyclopentylpropionate, free of 17ahydroxy compound, as shown by infrared spectrum. The yield of the desired ester is 60% of theory.

EXAMPLE VI 6OL-MCthyl Progesterone-1 7a-Ol rz-Butyrate By the procedure described in Example II above, a 75% yield of the desired butyric acid ester is obtained from 50 grams of n-butyric acid.

EXAMPLE VII Get-Methyl Prgester0ne-17a-Ol n-Hexanoate By the procedure described in Example II above, a 67% yield of the desired hexanoic acid ester is obtained from 50 grams of n-hexanoic acid.

EXAMPLE VIII 6a-M ethyl Pr0geszer0ne-17a-0l rz-Octanoate By the procedure described in Example II above, a 63% yield of the desired octanoic acid ester is obtained from 50 grams of n-octanoic acid.

EXAMPLE DC 6 u-M ethyl Progesterone-1 7a-Ol n-Heptanoate By the procedure described in Example II above, a 67% yield of the desired heptanoic acid ester is obtained from 50 grams of n-heptanoic acid.

EXAMPLE X 6 a-M ethyl -1 7 a-A cetoxy Pr0gester0ne-3-Ethylelze T hioketal To a solution of grams of 6a-methyl-l7a-acetoxyprogesterone in the minimum amount (5-15 ml.) of methylene chloride is added 5 ml. of ethanedithiol. This solution is stirred and chilled to 5, and then 2 ml. of 1.5 N ethereal hydrogen chloride is added in one portion. After five minutes at 5-10", the reaction mixture is held at 20 for ten minutes and then -70 ml. of methanol is added to effect precipitation of the B-ethylene thioketal. After chilling at 0 for thirty minutes, the suspension is filtered and the filter cake is washed with cold methanol.

The desired 3-ethylene thioketal is thus obtained in a state of high purity in a yield of 95% of theory. The product, after recrystallization from acetone, melts at 269- 272 C. with decomposition.

EXAMPLE XI 6a-Zllethyl17u-A cetoxy Progesterone-S-Propylene T hioketal The procedure described in Example IX above is repeated substituting for the 5 ml. of ethanedithiol an equivalent volume of 1,3-propanedithiol.

The desired 3-propylene dithioketal is obtained in a yield of 76% of theory. M.P. 250-257 C. with decomposition.

EXAMPLE XII 6a-Methyl-3-Bis Ethylthio-4-Pregnen-17ot-Ol-20-0ne Acetate The procedure described in Example X is repeated substituting for the 5 ml. of ethanedithiol, an equivalent volume of ethyl mercaptan. The desired 6rx-methyl-3-bis ethylthio-4-pregnen-17a-o1-20-one acetate is obtained in a yield of 92% of theory.

t EXAMPLE xIII 6u-Methyl-3-EthyIene T hioketal-4-Pregnen- 17a-0l-20-0ne Propionate The procedure described in Example X is repeated substituting for the 5 grams of 6a-methyl-l7a-acetoxy progesterone an equivalent weight of 6a-methyl progester- 0116-170c-O1 propionate.

The desired 6a-metl1yl-3-ethylene thioketal 4-pregnen- 17a-ol-20-one propionate is obtained in a yield of 87% of theory.

EXAMPLE XIV 6a-Methyl-3-Elhylene Thioketizll-Pregnen- 17a-Ol-20-One n-Valerate The procedure described in Example X is repeated substituting for the 5 grams of 6a-methyl-l7a-acetoxy progesterone an equivalent weight of 6rx-methyl progesterone-17a-ol n-valerate.

The desired 6a-methyl-3-ethylene thioketal 4-pregnen- 17e-ol-20-one n-valerate is obtained in a yield of of theory.

EXAMPLE XV 6a-Methyl-3-Ethylene Thioketal-4-Pregnen- 17a-0l-20-0ne Cyclopentylpropionale The procedure described in Example X is repeated substituting for the 5 grams of 6m-methyl-l7rx-acetoxy progesterone an equivalent weight of 6a-methyl progesterone-17a-ol cyclopentylpropionate.

The desired 6a-methyl-3-ethylene thioketal 4-pregnen- '17a-0l-20one cyclopentylpropionate is obtained in a yield of 83% of theory.

EXAMPLE XVI The procedure described in Example X is repeated substituting for the 5 grams of 6a-methyl-17a-acetoxy progesterone an equivalent weight of 6a-methyl progesterone-17a-ol n-butyrate.

The desired 6a-methyl-3-ethylene thioketal 4-pregnen- 70t-OI-20-OI'I3 n-butyrate is obtained in a yield of 76% of theory.

EXAMPLE XVII 6 rx-M ethy [-3 -E th ylcne T h i okeial -4 -Pregllen- 1 7 a-OI-ZO-One n-Hexanorzte The procedure described in Example X is repeated substituting for the 5 grams of 6a-methyl-17a-acetoxy progesterone an equivalent weight of 6a-methyl progesterone-ml n-hexanoate.

The desired 6oI-methyl-3-ethylene thioketal 4-prcgnenl7a-ol-20-one n-hexanoate is obtained in a yield of 78% of theory.

EXAMPLE XVIII 6a-Mcthyl-3-Et/zylene T lzi0kezal-4-Pregnen- 17a-Ol-20-One n-Octanoate 6ot-MetItyl-3-Ethylene T hi0ketal-4-Pregne/z- 17a-0l-20-0ne n-Heptanoale The procedure described in Example X is repeated sub stituting for the 5 grams of 6oI-methyl-l7a-acetoxy progesterone an equivalent weight of 6a-methyl progesterone- 1706-01 n-heptanoate.

The desired Ga-methyl-S-ethyIene thioketal 4-pregnen- 5 l7a-ol-20-one n-heptanoate is obtained in a yield of 67% of theory.

In the literature pertaining to inhibition of ovulation the term ovulation inhibition is frequently applied to a Wide time-span and physiological actions that may include the inhibition of follicular development through prolonged administration of inhibiting agents that generally act through inhibition of total ovarian activity, such as the natural hormones, estrogens, androgens, progestins.

The compounds of the present invention seem to effect an immediate ovulation stop, upon the short term or single administration of these compounds prior to expected ovulation.

It is to be understood that the invention is not to be limited to the exact details of operation or exact compounds shown and described as obvious modifications and equivalents will be apparent to one skilled in the art, and the invention is therefore to be limited only by the scope of the appended claims.

This application is a continuation-in-part of my copending application, Serial No. 125,995, filed July 24, 1961.

What is claimed is:

1. 6a-methyl-4-pregnen-17a-ol-20-one-3-ethylene thioketal.

2. 60LI1'1ethy1-170t-3.CetOXy progesterone-3-ethylene thioketal.

3. 6ot-methyl-17a-acetoxy progesterone-3-propylene thioketal.

4. 6a-methyl-3-bis-ethylthio-4-pregnen-17a-ol 20 one acetate.

5. 6a-methyl-3-ethylene thioketal-4-pregnen-17a-ol-20- one propionate.

6. 6ot-methyl-3-ethylene thioketal-4-pregnen-l7a-ol-20- one n-valerate.

(CHz)x-S i in Which x is an integer larger than one and smaller than four, and Y is a radical selected from the group consisting of hydrogen and alkanoyl radicals.

References Cited in the file of this patent UNITED STATES PATENTS Ralls et al. May 1, 1956 OTHER REFERENCES Babcock et al.: I.A.C.S., vol. 80, 1958, pp. 2905 and 2906. 

12. A COMPOUND HAVING THE STRUCTURE 